Hypertension, the "silent killer" is one of the leading causes of deaths in African Americans. In trying to identify those individuals that are prone to this disease, one must identify factors that influence cardiac output to psychological stressors. The proposed studies will examine the effects of aerobic fitness level, personality and cholesterol on cardiac reactivity to laboratory stressors. The first study will examine the effectiveness of tw forms of laboratory stressors. Cardiovascular activity and electromyographic activity will taken as subjects imagine or view a stressful racial scene on videotape. The second study will determine to what extent aerobic capacity, the Type A behavior pattern, Trait anxiety an Black Consciousness affect the heart rate, contractility force and cardiac output of 30 males and 30 females as they watch a stress inducing videotape It is hypothesized that there will be greater reactivity for low fit individuals. This reactivity is also proposed for Type A individuals and individuals high in anxiety. Last, it is hypothesized that those participants scoring high in Black Consciousness will have higher levels of responding to the videotape than their counterparts. The third study will investigate the efficacy of serum cholesterol as a predictor of cardiac reactivity to a stressful videotape an a bicycle ergometer in 30 male and 30 female college students. Measures of total serum cholesterol, high density lipoprotein cholesterol (HDL), low density lipoprotein cholesterol (LDL) and triglycerides will be assessed at a local medical facility. Thes measures will also be compared to the Type A behavior pattern, Trait anxiet & Black Consciousness. Because this is an exploratory study, no prediction will be made.